Beverage can end frangible score geometry

Abstract

An ecology stay-on tab beverage can end has a first axis extending though a rivet. A tear panel is defined by a frangible score and a non-frangible hinge that joins a first end of the frangible score with a second end of the frangible score. The first axis forms a line of asymmetry of the tear panel. A second axis intersects the first axis at a right angle. An intersection of the first axis with the second axis defines a center point of a clock-like reference having a 12 o'clock position at the first point and a 6 o'clock position at the second point. A first radius of curvature of the frangible score between a 5 o'clock position and a 7 o'clock position is at least 3.6 times larger than a second radius of curvature between a 7 o'clock position and a 9 o'clock position.

What is claimed is: 
     
       1. An ecology stay-on tab beverage can end comprising:
 a circumferential curl centered about a longitudinal axis; 
 a circumferential wall extending downwardly from the curl; 
 a circumferential strengthening member located downwardly from the wall; and 
 a center panel located radially inwardly from the strengthening member and centered about the longitudinal axis comprising:
 a tab having a lift end opposite a nose end; 
 a rivet attaching a tab to the center panel; 
 a first axis extending through the rivet, the lift end of the tab, and the nose end of the tab and perpendicular to the longitudinal axis; 
 a tear panel defined by a frangible score and a non-frangible hinge that joins a first end of the frangible score with a second end of the frangible score, wherein the first axis forms a line of asymmetry of the tear panel; and 
 a second axis intersecting the first axis at a right angle at a midpoint of a first axis segment defined by a length between a first point where the first axis intersects the frangible score near the rivet and a second point where the first axis intersects the frangible score and which is located radially outwardly of the first point, wherein an intersection of the first axis with the second axis defines a center point of a clock-like reference of the frangible score having a 12 o'clock position at the first point and a 6 o'clock position at the second point, 
 wherein the frangible score has a convex first radius of curvature between a 5 o'clock position and a 7 o'clock position that is at least 3.6 times larger than a convex second radius of curvature between a 7 o'clock position and a 9 o'clock position, and 
 wherein a convex third radius of curvature located between a 1 o'clock position and a 2 o'clock position is less than a convex fourth radius of curvature between the 1 o'clock position and a 4 o'clock positions wherein the fourth radius of curvature intersects a 3 o'clock position. 
 
 
     
     
       2. The ecology stay-on tab beverage can end of  claim 1  wherein the first radius of curvature between a 5 o'clock position and a 7 o'clock position that is at least 4.5 times larger than the second radius of curvature between a 7 o'clock position and a 9 o'clock position. 
     
     
       3. The ecology stay-on tab beverage can end of  claim 1  wherein the first radius of curvature between a 5 o'clock position and a 7 o'clock position that is between 4.5 to 10 times larger than the second radius of curvature between a 7 o'clock position and a 9 o'clock position. 
     
     
       4. The ecology stay-on tab beverage can end of  claim 1  wherein the tear panel has a surface area between 0.50 square inches (3.23 cm 2 ) and 0.80 square inches (5.16 cm 2 ). 
     
     
       5. The ecology stay-on tab beverage can end of  claim 1  further comprising a tear panel opening sequence wherein lifting upwardly on the lift end of the tab causes a fracture of the frangible score to propagate clockwise towards the second end of the frangible score and wherein the tear panel is deflected downwardly about the hinge segment. 
     
     
       6. The ecology stay-on tab beverage can end of  claim 1  further comprising:
 a third axis intersecting the first axis at a right angle at a distance from the first point on the frangible score located radially outwardly from the midpoint of the first axis segment relative to the longitudinal axis and having a third axis segment defined by a length of the third axis between a fifth point on the frangible score and a sixth point on the frangible score, 
 wherein a ratio of the length of the third axis segment to the length of the first axis segment is greater than 1.2. 
 
     
     
       7. The ecology stay-on tab beverage can end of  claim 1  wherein a second axis segment is defined by a length of the second axis between a third point on the frangible score located at the 3 o'clock position and a fourth point on the frangible score located at the 9 o'clock position; and further comprising:
 a third axis intersecting the first axis at a right angle at a distance from the first point on the frangible score located radially outwardly from the midpoint of the first axis segment relative to the longitudinal axis and having a third axis segment defined by a length of the third axis between a fifth point on the frangible score and a sixth point on the frangible score, 
 wherein a ratio of the length of the second axis segment to the length of the third axis segment is less than 1.0. 
 
     
     
       8. The ecology stay-on tab beverage can end of  claim 1  further comprising:
 an anti-fracture score located radially inwardly of the frangible score relative to the center point of the clock-like reference and generally following the shape thereof. 
 
     
     
       9. The ecology stay-on tab beverage can end of  claim 1  further comprising:
 a deboss panel in which the tear panel and the rivet are recessed in the center panel. 
 
     
     
       10. The ecology stay-on tab beverage can end of  claim 1  wherein the circumferential strengthening member is a generally U-shaped countersink. 
     
     
       11. The ecology stay-on tab beverage can end of  claim 1  wherein the can end is a 209-sized can end. 
     
     
       12. The ecology stay-on tab beverage can end of  claim 1  wherein the can end is a 202-sized can end. 
     
     
       13. An ecology stay-on tab beverage can end comprising:
 a circumferential curl centered about a longitudinal axis; 
 a circumferential wall extending downwardly from the curl; 
 a circumferential strengthening member located downwardly from the wall; and 
 a center panel located radially inwardly from the strengthening member and centered about the longitudinal axis comprising:
 a tab having a lift end opposite a nose end; 
 a rivet attaching a tab to the center panel; 
 a first axis extending through the rivet, the lift end of the tab, and the nose end of the tab and perpendicular to the longitudinal axis; 
 a tear panel defined by a frangible score and a non-frangible hinge that joins a first end of the frangible score with a second end of the frangible score, wherein the first axis forms a line of asymmetry of the tear panel; 
 a second axis intersecting the first axis at a right angle at a midpoint of a first axis segment defined by a length of the first axis between a first point where the first axis intersects the frangible score near the rivet and a second point where the first axis intersects the frangible score which is located radially outwardly of the first point, wherein an intersection of the first axis with the second axis defines a center point of a clock-like reference of the frangible score having a 12 o'clock position at the first point and a 6 o'clock position at the second point; and 
 a third axis intersecting the first axis at a right angle at a distance from the first point on the frangible score located radially outwardly from the midpoint of the first axis segment relative to the longitudinal axis and having a third axis segment defined by a length of the third axis between a fifth point on the frangible score and a sixth point on the frangible score, 
 wherein a ratio of the length of the third axis segment to the length of the first axis segment is greater than 1.2. 
 
 
     
     
       14. The ecology stay-on tab beverage can end of  claim 13  wherein the ratio is between 1.2 and 1.5. 
     
     
       15. The ecology stay-on tab beverage can end of  claim 13  wherein the ratio is between 1.27 and 1.46. 
     
     
       16. The ecology stay-on tab beverage can end of  claim 13  wherein in a 202-sized can end, the ratio is between 1.40 and 1.46. 
     
     
       17. The ecology stay-on tab beverage can end of  claim 13  wherein a 209-sized can end, the ratio is between 1.27 and 1.30. 
     
     
       18. The ecology stay-on tab beverage can end of  claim 13  wherein the tear panel has a surface area between 0.50 square inches (3.23 cm 2 ) and 0.80 square inches (5.16 cm 2 ). 
     
     
       19. The ecology stay-on tab beverage can end of  claim 13  further comprising a tear panel opening sequence wherein lifting upwardly on the lift end of the tab causes a fracture of the frangible score to propagate clockwise towards the second end of the frangible score and wherein the tear panel is deflected downwardly about the hinge segment. 
     
     
       20. The ecology stay-on tab beverage can end of  claim 13  further comprising:
 an anti-fracture score located radially inwardly of the frangible score relative to the center point of the clock-like reference and generally following the shape thereof. 
 
     
     
       21. The ecology stay-on tab beverage can end of  claim 13  further comprising:
 a deboss panel in which the tear panel and the rivet are recessed in the center panel. 
 
     
     
       22. The ecology stay-on tab beverage can end of  claim 13  wherein the circumferential strengthening member is a generally U-shaped countersink. 
     
     
       23. The ecology stay-on tab beverage can end of  claim 13  wherein the can end is a 209-sized can end. 
     
     
       24. The ecology stay-on tab beverage can end of  claim 13  wherein the can end is a 202-sized can end. 
     
     
       25. The ecology stay-on tab beverage can end of  claim 13  wherein a second axis segment is defined by a length of the second axis between a third point on the frangible score located at the 3 o'clock position and a fourth point on the frangible score located at the 9 o'clock position, and wherein a ratio of the length of the second axis segment to the length of the third axis segment is less than 1.0. 
     
     
       26. An ecology stay-on tab beverage can end comprising:
 a circumferential curl centered about a longitudinal axis; 
 a circumferential wall extending downwardly from the curl; 
 a circumferential strengthening member located downwardly from the wall; and 
 a center panel located radially inwardly from the strengthening member and centered about the longitudinal axis comprising:
 a tab having a lift end opposite a nose end; 
 a rivet attaching a tab to the center panel; 
 a first axis extending through the rivet, the lift end of the tab, and the nose end of the tab and perpendicular to the longitudinal axis; 
 a tear panel defined by a frangible score and a non-frangible hinge that joins a first end of the frangible score with a second end of the frangible score, wherein the first axis forms a line of asymmetry of the tear panel; 
 a second axis intersecting the first axis at a right angle at a midpoint of a first axis segment defined by a length of the first axis between a first point where the first axis intersects the frangible score near the rivet and a second point where the first axis intersects the frangible score which is located radially outwardly of the first point, wherein an intersection of the first axis with the second axis defines a center point of a clock-like reference of the frangible score having a 12 o'clock position at the first point and a 6 o'clock position at the second point, wherein a second axis segment is defined by a length of the second axis between a third point on the frangible score located at the 3 o'clock position and a fourth point on the frangible score located at the 9 o'clock position; and 
 a third axis intersecting the first axis at a right angle at a distance from the first point on the frangible score located radially outwardly from the midpoint of the first axis segment relative to the longitudinal axis and having a third axis segment defined by a length of the third axis between a fifth point on the frangible score and a sixth point on the frangible score, 
 wherein a ratio of the length of the second axis segment to the length of the third axis segment is less than 1.0. 
 
 
     
     
       27. The ecology stay-on tab beverage can end of  claim 26  wherein the third axis extends across a maximum width of the frangible score which is located radially outwardly of the midpoint of the first axis segment relative to the longitudinal axis. 
     
     
       28. The ecology stay-on tab beverage can end of  claim 26  wherein the tear panel has a surface area between 0.50 square inches (3.23 cm 2 ) and 0.80 square inches (5.16 cm 2 ). 
     
     
       29. The ecology stay-on tab beverage can end of  claim 26  further comprising a tear panel opening sequence wherein lifting upwardly on the lift end of the tab causes a fracture of the frangible score to propagate clockwise towards the second end of the frangible score and wherein the tear panel is deflected downwardly about the hinge segment. 
     
     
       30. The ecology stay-on tab beverage can end of  claim 26  further comprising:
 an anti-fracture score located radially inwardly of the frangible score relative to the center point of the clock-like reference and generally following the shape thereof. 
 
     
     
       31. The ecology stay-on tab beverage can end of  claim 26  further comprising:
 a deboss panel in which the tear panel and the rivet are recessed in the center panel. 
 
     
     
       32. The ecology stay-on tab beverage can end of  claim 26  wherein the circumferential strengthening member is a generally U-shaped countersink. 
     
     
       33. The ecology stay-on tab beverage can end of  claim 26  wherein the can end is a 209-sized can end. 
     
     
       34. The ecology stay-on tab beverage can end of  claim 26  wherein the can end is a 202-sized can end.